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Abstract:

A measuring apparatus for measuring a counterbore hole chamfer depth of a
workpiece, includes a positioning member having a guiding hole aligned
with the counterbore hole of the workpiece, a support member having a
receiving hole aligned with the guiding hole, and a measuring device
supported by the support member. The measuring device includes a gauge, a
retractable pole connected to the gauge and extending into the receiving
hole, and a measuring head portion connected to the retractable pole and
movably received in the guiding hole. The measuring head portion has a
cone-shaped end for abutting on an inner wall of the counterbore hole
chamfer, thereby making the measuring head portion move back in the
guiding hole and the retractable pole retract. The gauge is configured
for calculating and displaying the depth of the counterbore hole chamfer
based on the distance the retractable pole retracts.

Claims:

1. A measuring apparatus for measuring a counterbore hole chamfer depth
of a workpiece, comprising: a positioning member configured for
positioning the workpiece, the positioning member comprising a guiding
hole for alignment with the counterbore hole of the workpiece; a support
member positioned on the positioning member, the support member
comprising a receiving hole aligned with the guiding hole; and a
measuring device supported by the support member, the measuring device
comprising a gauge, a retractable pole connected to the gauge and
extending into the receiving hole, and a measuring head portion connected
to the retractable pole and movably received in the guiding hole, the
measuring head portion having a cone-shaped end with a cone angle less
than a chamfer angle of the counterbore hole, the cone-shaped end
extending through the guiding hole and configured for abutting an inner
wall of the counterbore hole chamfer, thereby making the measuring head
portion moving back in the guiding hole and the retractable pole
retracted a distance, the gauge configured for calculating and displaying
a depth of the counterbore hole chamfer based on the retracted distance
of the retractable pole.

2. The measuring apparatus of claim 1, wherein the positioning member
comprises a guiding block and a plurality of magnetic blocks, the guiding
block includes two recesses for facing the workpiece, the guiding hole is
formed in the guiding block, the magnetic blocks are entirely received in
the respective recesses and configured for magnetically attracting the
workpiece.

3. The measuring apparatus of claim 1, wherein the measuring device
further comprises a spring member having a first end connected to the
measuring head portion, and an opposite second end abutting on an inner
wall of the receiving hole.

4. The measuring apparatus of claim 3, wherein the receiving hole
includes a first hole section adjacent to the positioning member, an
opposite second hole section, and a third hole section located between
the first hole section and the second hole section, a diameter of the
third hole section being less than that of the first hole section and
that of the second hole section, thereby forming a first step between the
first hole section and the third hole section and a second step between
the second hole section and the third hole section, the second end of the
spring member abutting on the first step.

5. The measuring apparatus of claim 1, wherein the measuring device
further comprises a sheath surrounding the retractable pole, and a sleeve
receiving the sheath, the sleeve being positioned on the support member.

6. A method for measuring a counterbore hole chamfer depth of a
workpiece, comprising: providing a measuring apparatus of claim 1;
providing a workpiece having a counterbore hole having a counterbore hole
chamfer exposed at a first surface of the workpiece and a bottom hole
exposed at an opposing second surface of the workpiece; attaching the
workpiece to the positioning member with the second surface of the
workpiece facing toward and contacting the positioning member, thereby
the cone-shaped end of the measuring head portion and the retractable
pole being retracted a first distance; setting the gauge back to zero;
attaching the workpiece to the positioning member with the first surface
of the workpiece facing toward and contacting the positioning member,
thereby the cone-shaped end of the measuring head portion and the
retractable pole retracted a second distance; calculating a depth of the
counterbore hole chamfer depth based on the second distance using the
gauge; and displaying the depth of the counterbore hole chamfer depth on
the gauge.

Description:

[0004] In assembly of various devices, articles with counterbore holes are
widely used for being connected to each other with counterbore head
screws. The counterbore holes are usually chamfered for facilitating the
mounting of the counterbore head screws. A depth of the counterbore hole
chamfer needs to be checked, to ensure that heads of the screws are flush
with the surrounding surface.

[0005] Currently, a caliper is usually used to test the counterbore hole
chamfer depth. However, accurate placement of the caliper is not easily
achieved, which can effect the precision of measuring the chamfer.

[0006] What is needed, therefore, is a counterbore hole chamfer depth
measuring apparatus and method, which can overcome the above
shortcomings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Many aspects of the present measuring apparatus and method can be
better understood with reference to the following drawings. The
components in the drawings are not necessarily drawn to scale, the
emphasis instead being placed upon clearly illustrating the principles of
the present measuring apparatus and method. Moreover, in the drawings,
like reference numerals designate corresponding parts throughout the
several views.

[0008] FIG. 1 is an isometric view of a counterbore hole chamfer depth
measuring apparatus in accordance with an embodiment.

[0009] FIG. 2 is a cross-sectional view of the measuring apparatus of FIG.
1, taken along the II-II line.

[0010] FIG. 3 is an exploded view of the measuring apparatus of FIG. 1.

[0011] FIG. 4 is schematic view of a workpiece having a counterbore hole
chamfer.

[0012] FIG. 5 and FIG. 6 show steps of measuring the counterbore hole
chamfer depth of the workpiece of FIG. 4 with the measuring apparatus
shown in FIG. 2.

DETAILED DESCRIPTION

[0013] Embodiments of the present measuring apparatus and method will now
be described in detail below and with reference to the drawings.

[0014] Referring to FIG. 1, a measuring apparatus 10 for whether a
counterbore hole chamfer is done to the proper depth, includes a
positioning member 20, a support member 30, and a measuring device 40.

[0015] Referring also to FIGS. 2 and 3, the positioning member 20 includes
a guiding block 21 and two magnetic blocks 22. The guiding block 21 is
substantially rectangular, and includes a first surface 23 and an
opposite second surface 24. The guiding block 21 includes a guiding hole
26 defined through the first surface 23 and the second surface 24, two
recesses 25 defined in the first surface 23, and two first engaging holes
27 defined in the second surface 24 and in communication with the
recesses 25, respectively. A central axis of each of the first engaging
holes 27 is aligned with that of the corresponding recess 25. The
magnetic blocks 22 are completely received in the respective recesses 25
(see FIG. 2).

[0016] The support member 30 is fixed on the second surface 24 of the
positioning member 20. The support member 30 includes a support block 31,
two first screws 32, and a second screw 33. The support block 31 includes
a main body 311 and two side blocks 36 extending from opposite sides of
the main body 311. The main body 311 is substantially rectangular, and
includes a first end 34 and a second end 35 along a lengthwise direction
of the main body 311. The first end 34 is in contact with the second
surface 24 of the guiding block 21. The side blocks 36 are located at the
first end 34, and the side blocks 36 are in contact with the second
surface 24. Each of the side blocks 36 has a second engaging hole 37
defined therein. Each of the second engaging holes 37 corresponds to one
of the first engaging holes 27, and a central axis of the second engaging
hole 37 is aligned with that of the corresponding first engaging hole 27.
Each of the first screws 32 engages in one of the second engaging holes
37 and the corresponding first engaging hole 27, such that the support
block 31 is fixed to the guiding block 21.

[0017] A receiving hole 310 is formed through the first end 34 and the
second end 35 of the main body 311. The receiving hole 310 is composed of
a first hole section 301 at the first end 34, a third hole section 302 at
the second end 35, and a second hole section 312 located between the
first hole section 301 and the third hole section 302. A diameter of the
first hole section 301 is substantially equal to the that of the third
hole section 302, and is greater than that of the guiding hole 26. A
diameter of second hole section 302 is less than that of the first hole
section 301 and that of the third hole section 302, such that a first
step surface 313 is formed between the first hole section 301 and the
second hole section 312, and a second step surface 314 is formed between
second hole section 312 and the third hole section 302. The first step
surface 313 is exposed at the first hole section 301, and the second step
surface 314 is exposed at the third hole section 302.

[0018] A threaded hole 304 is defined in a sidewall 303 of the main body
311, in communication with the third hole section 302. The second screw
33 is engaged in and extends through the threaded hole 304.

[0019] The measuring device 40 includes a measurement instrument 41, a
spring member 42, a measuring head portion 43, and a sleeve 44. The
measurement instrument 41 includes a gauge 47, a sheath 45 and a
retractable pole 46 extending through the sheath 47 and connected to the
gauge 47. The gauge 47 indicates how far the retractable pole 46 is
extended or retracted, and a zero point can be marked. The measuring head
portion 43 has a proximal end 48 and an opposite distal end 49. The
proximal end 48 has a cone with a cone angle less than the counterbore
hole chamfer angle α of the workpiece 50 (see FIG. 4). The
measuring head portion 43 is movably received in the guiding hole 26 of
the guiding block 21, and the proximal end 48 extends through the guiding
hole 26. The distal end 49 is columnar, and a diameter of the distal end
49 is greater than that of the guiding hole 26. The retractable pole 46
extends through the sheath 45 and extends into the receiving hole 310.
The end of the retractable pole 46 is connected to the distal end 49. The
spring member 42 is received in the first hole section 301, and has a
first end connected to the distal end 49 and a second end abutting on the
first step surface 313. The spring member 42 can be in an uncompressed
state when no force is applied to the measuring head portion 43.

[0020] The sleeve 44 is substantially cylindrical, and has an opening 441
defined in a sidewall along a lengthwise direction thereof. The sleeve 44
is received in the third hole section 302, and the sheath 45 is received
in the sleeve 44. The second screw 33 extends through the threaded hole
304 and abuts on the sleeve 44, such that the measurement instrument 41
is fixed on the support member 30.

[0021] Referring to FIG. 4, in application, a workpiece 50 to be tested is
provided. The workpiece 50 includes a counterbore hole chamfer 51 exposed
to a first surface 53 and a bottom hole 52 exposed to an opposite second
surface 54. The counterbore hole chamfer 51 and the bottom hole 52 form a
counterbore hole, and the counterbore hole chamfer 51 forms a step
between the counterbore hole chamfer 51 and the bottom hole 52. A depth h
of the counterbore hole chamfer 51 is to be measured.

[0022] Firstly, referring also to FIG. 5, the workpiece 50 is placed under
the guiding block 21, with the second surface 54 which the bottom hole 52
exposed to face toward the guiding block 21. The magnetic blocks 22 can
help to position the workpiece 50 if the workpiece 50 is metallic, and if
the workpiece 50 is non-metallic, force can be applied between the
workpiece 50 and the guiding block 21 to help position the workpiece 50.

[0023] As the proximal end 48 of the measuring head portion 43 protrudes
out of the guiding hole 26, the proximal end 48 first contacts the second
surface 54 of the workpiece 50. However, as the measuring head portion 43
can move in the guiding hole 26, and the retractable pole 46 can retract,
the measuring head portion 43 together with the retractable pole 46 will
move back until the first surface 23 of the guiding block 26 contacts the
second surface 54 of the workpiece 50.

[0024] The gauge 47 can store the movement distance, i.e., the retracted
distance of the retractable pole 46. In order to obtain the depth h of
the counterbore hole chamfer 51, this retracted distance is set to zero.

[0025] Next, referring also to FIG. 6, the workpiece 50 is turned over,
with the first surface 53 from which the counterbore hole chamfer 51 is
exposed, faces the guiding block 21. Before the proximal end 48 extends
into the counterbore hole chamfer 51, the spring member 42 restores the
measuring head portion 43 together with the retractable pole 46 move to
an original position. The proximal end 48 of the measuring head portion
43 may contact an inner wall of the counterbore hole chamfer 51 as the
proximal end 48 extends into the counterbore hole chamfer 51. However, as
the measuring head portion 43 can move in the guiding hole 26, and the
retractable pole 46 can retract, the measuring head portion 43 together
with the retractable pole 46 will move back until the first surface 23 of
the guiding block 26 contacts the first surface 53 of the workpiece 50.

[0026] At this time, the gauge 47 can show a retracted distance relative
to the previous retracted distance. As the previous retracted distance is
set to zero, any difference is the depth of the counterbore hole chamfer
51. The relative measurement makes the measuring of the counterbore hole
chamfer depth more precise.

[0027] It is understood that the above-described embodiments are intended
to illustrate rather than limit the disclosure. Variations may be made to
the embodiments and methods without departing from the spirit of the
disclosure. Accordingly, it is appropriate that the appended claims be
construed broadly and in a manner consistent with the scope of the
disclosure.